Air-brake.



Patented 1an. 8, |901. W. F. KNELL.

AIR BRAKE.

(Application led Sept. 7, 1899.)

(No Modal.)

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UNTED STATES ATENT Frio WILLIAM F. KNELL, OF BATTLE CREEK, MICHIGAN, ASSIGNOR OF TWO- THIRDS TO FRANK F. BOOK, OF SAME PLACE, AND GEORGE G. TAN- NER, OF INDIANAPOLIS, INDIANA.

AIR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 665,607, dated January 8, 1901.

Application f1ed September '7, 1899.

['0 all whom, t may concern:

Be it known that I, WILLIAM F. KNELL, a citizen of the United States, residing at Battle Creek, in the county of Calhoun and State of Michigan, haveinvented certain new and useful Improvements in Air-Brakes, of which the following is a specification.

The object of my present invention is to simplify that class of brake apparatus, principally used on railways, in which a reduction of pressure in the supply -or train pipe automatically causes the brakes to be applied to the wheels. Its distinguishing feature is a structure embodying two cylinders, one of which is smaller than the other and is surrounded by an auxiliary chamber to contain a suitable amount of compressed air to accomplish the work. A piston-rod passes through the division-wall which separates these two cylinders and bears upon each end a piston, the smaller of which is contained within the smaller cylinderjust referred to and the larger one in a larger cylinder upon the opposite end. Branches from the train-pipe communicate with both these cylinders or with chambers connected therewith. In the branch through which communication is had with the smaller cylinder, or rather, preferably, with the auxiliary chamber thereto, there is a check-valve; but that branch communicating `with the larger cylinder is wholly unobstructed. The result is that air may flow into and out of the larger cylinder freely as the pressure increases or decreases in the train-pipe, while there is no change in the quantity of air in the smaller cylinder and in its auxiliary chamber, except the loss, if any, through leakage, which is immediately supplied when the pressure in the train-pipe attains its maximum again. As is therefore obvious, the piston is driven back and forth, and the brake mechanism is thus operated merely by decreasing and increasing the pressure in the train-pipe, Which is effectuated in the ordinary and well-known manner. The pressure in the process of applying the brakes decreases until the pressure on the smaller piston is capable of overcoming the resistance against the larger piston, and the brake mechanism is operated until the pressure on the two sides (taking the size of the re- Serial No. 729,717. (No model.)

`spective pistons into consideration) has been equalized. In the process of removing the brakes the pressure in the train-pipe increases until by reason of the superior area of the larger piston it is enabled to force the smaller piston back to the limit of its stroke, where it is held until the train-pipe pressure is again decreased.

I will now proceed to describe an apparatus embodying said invention in detail.

Referring to the accompanying drawings, which are made a part hereof and on which similar reference characters indicate similar parts, Figure lis a side elevation of a portion of a railway-train equipped with a railway brake apparatus embodying my present invention; Fig. 2, a top or plan View of the airbrake apparatus separately, and Fig. 3 is a longitudinal sectional View of the cylinders peculiar to my present invention with the piston-rod and pistons in place and fragments of the pipes and immediately-adjacent parts attached.

All those features illustrated in the drawings, except those which will be presently described, are such as used in a common and well-known and widely-used form of air-brake apparatus and will not, therefore, be especially described herein, except incidentallyin describing the invention, as they are all constructed, connected, and operated in a manner well known to those skilled in the art.

The train-pipe l contains air under pressure supplied from the usual air-pumping apparatus and has branches2 and 3, which lead, respectively, to the larger cylinder 4 and to the auxiliary chamber 5, connected with and surrounding the smaller cylinder 6. In the branch 3 is a check-valve 7. A piston-rod 8 is connected to the brake-operating mechanism and has a larger p iston 9 thereon in the larger cylinder and a smaller piston l0 on the other end in the smaller cylinder.

The advantages of embodying the cylinders 4 and 6 and the auxiliary chamber 5 in a single structure instead of providing aseparate auxiliary chamber distant from the cylinders will be readily understood. In the construction shown the means of communication is not only of much greater area, but is immediately connected with the parts, so that the air may without the application of any ap preciable force flow from the auxiliary chamber 5 to the cylinder 6, or vice versa, freely and instantly. All the labor of coupling up the parts, as well as the material necessary to make such couplings, is also saved, as is clearly apparent upon an inspection of the drawings.

Supposing now that the air-pressu re is commonly maintained in the pipe at seventy pounds, it is perfectly obviousthat this pressure will be equal upon the two pistons 9 and 10, and the piston 9 being the larger will force the piston lO to'the limit of its stroke, and the connections being properly made the brakes will be held from contact with the wheels. When it is desired to apply the brakes, the air is permitted to escape, so that the air-pressure is reduced in the train-pipe, and consequently in the larger cylinder. As the air in the small cylinder is confined, as soon as the reduction in pressure has reached the proper point the smaller piston will actnate the piston-rod and set the brakes. When it is desired to remove the brake-pressure, it is readily done by forcing a new supply ot air into the train-pipe, and thus restoring pressure in the larger cylinder, so that the piston 9 will operate, as will be easily understood. An opening at 0 in the cylinder 4 behind the pis ton 9 permits a free ingress and egress ot' air behind said piston as its movements may require.

It is clear that in opening the appropriate valve to reduce pressure in the train-pipe and in the cylinder containing the larger piston the manipulation may be such that any desired quantity of air may be discharged and the pressure thus reduced to any desired extent. Any movement of the pistons up to the limit of stroke provided for may thus be had in any case, so that a slight or gradual application of the brake may be had, as well as an application involving the entire power of the apparatus, at will. It will also be noticed that the air used in applying the brake is never discharged, so that it is always ready for use. There is consequently no time lost in recharging the braking-cylinder, and consequently never any possibility of delay in cases of emergency. This feature is of very great importance, as will be readily understood.

This apparatus is of the utmost simplicity, and consequently is not liable to get out of order, while its cost is lnuch less than that of former appliances for performing this work.

Having thus fn lly described my said in ven tion, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination, in a brake apparatus, of two cylinders of different sizes contained within the same structure and communicating with each other, two pistions one located in each cylinder and fitting the same, a single piston-rod connected to the brake mechanism upon which both pistons are mounted, an auxiliary chamber in the same structure with the cylinders and surrounding and communicating with the smaller cylinder, a train-pipe for conveying air under pressure to the cylinders, an open branch from said trainpipe to the larger cylinder, a branch from said train-pipe to the smaller cylinder, and a check-Valve in said branch, said several parts being constructed, arranged and operating substantially as set forth.

2. The combination, in an air-brake apparatus, with the usual levers, rods and brakebars, of a piston for-operating the same, two piston-heads of different sizes for operating said piston in opposite directions, two cylinders also of different sizes within which said piston-heads are located, an auxiliary chamber in the same structure with the cylinders and communicating with the smaller cylinder, a main pipe for conveying air under pressure to the apparatus, an unobstructed branch leading vfrom said main pipe to the larger cylinder, and a branch leading from said main pipe containing a check-valve and leading to the auxiliary chamber commui'iicating with the smaller cylinder, substantially as shown and described. p

The combination, in an air-brake apparatus, with the levers, rods and brake-bars, of a cylinder structure comprising two cylinders extending in opposite directions from a central partition thereof, one or" said cylinders being the full size of the structure and the other being composed of an annular cylindrical flange extending out from the said central partition toward the opposite end, the remaining space forming an auxiliary chamber which communicates with the outer end of said smaller cylinder inside the head ot' the structure which incloses the same as shown, the said central partition having an opening leading from the larger to the smaller cylinder larger. than the diameter of the pistonrod which passes through it, said piston-rod, and two piston-heads on said piston-rod one of the size ot the larger cylinder and the other of the size of the smaller cylinder, the larger cylinder being provided with a perforation leading to the outer air close to said .central partition, a train-pipe, and branch pipes leading therefrom to the larger cylinder and to the auxiliary chamber respectively, the Whole being constructed and arranged substantially as shown and described.

In witness whereof I have hereunto set my hand and seal at Indianapolis, Indiana, this 4th day of September, A. D. 1899.

WILLIAM F. KNELL.

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